Variable Displacement Pump Fuel Supply System for Turbomachines
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Solution Overview
Problem
The existing fuel supply system in turbomachines faces inefficiencies due to a surplus of fuel flow rate, leading to increased power draw and thermal dissipation, which negatively impacts the turbomachine's efficiency and requires larger, heavier fuel circuits.
Innovation Solution
A fuel supply system with a flow rate sensor and a controllable pump speed drive, allowing the rotational speed of the pump to be adjusted based on flow rate measurements to match the fuel flow rate to the turbomachine's operating conditions, thereby minimizing power draw and eliminating the need for a recirculation loop and certain hydromechanical components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pump displacement is dimensioned to deliver sufficient flow rate at all operating speeds, then the fuel flow rate requirement is met during all flight conditions, but the pump delivers excess flow rate during cruise flight, creating a fuel surplus and increasing power draw
Solution Approach 1:
The patent applies dynamics by making the pump displacement variable rather than fixed. The pump displacement is dynamically adjusted based on the operating speed of the turbomachine, allowing the system to adapt to different fuel flow requirements. This resolves the contradiction by enabling the pump to deliver accurate flow rates across all speeds without creating excess fuel surplus during cruise flight, thereby reducing unnecessary power draw.
Solution Approach 2:
The patent changes the parameter of pump displacement from a fixed design value to a variable parameter that depends on the operating speed. By making displacement a function of speed, the system can optimize fuel delivery for each operating condition, eliminating the need to over-size the pump for peak demand and reducing energy consumption during lower demand periods.
2Reliability
If the pump delivers excess flow rate to meet minimum fuel requirements, then the fuel flow rate is sufficient for all operating conditions, but the surplus fuel must be returned through a recirculation loop, increasing thermal dissipation and requiring larger heat exchangers
Solution Approach 1:
The dynamic adjustment of pump displacement based on operating speed eliminates the need for a recirculation loop. By matching the pump's fuel delivery to the actual requirements of the combustion chamber at each speed, the system avoids creating excess fuel that would need to be recirculated and dissipated as heat, thereby reducing thermal energy loss.
Solution Approach 2:
The patent extracts and eliminates the recirculation loop from the system by properly sizing the pump displacement at each operating point. This removal of the recirculation path eliminates the associated thermal dissipation problem and reduces the need for large heat exchangers.
3Reliability
If the pump displacement is increased to ensure sufficient flow rate at high speed, then the fuel flow rate requirement is met during take-off, but the pump delivers excessive flow rate during cruise flight, creating a fuel surplus
Solution Approach 1:
The patent applies dynamics by making the pump displacement variable rather than fixed. The pump displacement is dynamically adjusted based on the operating speed of the turbomachine, allowing the system to adapt to different fuel flow requirements. This resolves the contradiction by enabling the pump to deliver accurate flow rates across all speeds without creating excess fuel surplus during cruise flight.
Solution Approach 2:
The patent changes the parameter of pump displacement from a fixed design value to a variable parameter that depends on the operating speed. By making displacement a function of speed, the system can optimize fuel delivery for each operating condition, eliminating the need to over-size the pump for peak demand and reducing energy consumption during lower demand periods.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution optimizes power usage by matching fuel flow rate to demand, reduces the size and mass of the fuel circuit, and simplifies the hydromechanical system, leading to improved turbomachine efficiency and reduced thermal dissipation.
Implementation Method 1
a sensor for detecting the position of said drawer, the position of said drawer being controlled by a pressure difference across the flow rate sensor
Implementation Method 2
a pump (1) arranged to send into said circuit a fuel flow rate which is an increasing function of the rotational speed of a shaft of the pump
Data Source
AI summary
The present disclosure relates to a system for supplying fuel to a turbomachine. In some embodiments, a fuel circuit includes a pressurisation valve at an outlet of the system and a pump. The circuit may include a flow rate sensor arranged between the outlet of the pump and the pressurisation valve. In some embodiments, the flow rate sensor may include a sliding drawer, a restoring spring, and a sensor for detecting the position of said drawer in order to indicate the flow passing through the flow rate sensor. The system may include a device arranged to drive the pump with a controllable rotational speed and a control configured to control the device on the basis of a measurement supplied by the flow rate sensor, in such a way as to adapt the rotational speed of the pump shaft.